Thermoplastic coated paperboard containers are commonly utilized for storage and retention of different materials, including liquids such as milk, juice and creams, as well as solids, gels and other known materials which can be effectively stored for a period of time, e.g. a few days to a few weeks or so, in this type of container. Such thermoplastic coated cartons are generally formed in the manner of a gabled container and have been used for several decades to contain all types of fluids, solids, powders, and other materials with reasonable success. One drawback, however, with the use of such cartons is the quality and adequacy of the seams and seals along which the paperboard is cut and folded to form the resulting container. In particular, it is the bottom surface of such containers where the contents of the container are in almost continuous and constant contact with the formed seams, folds and exposed edges of the paperboard which causes failure in the integrity of the container bottom.
A gable carton is typically formed from a single blank of paperboard material with an array of score lines about which the paperboard material is folded to form the resulting carton. With reference to FIG. 1, a typical blank for a prior art half gallon gable carton is identified generally by the numeral 10. The prior art blank 10 includes first through fourth rectangular side wall panels 12, 14, 16, and 18 and a side glue panel 20 which are consecutively articulated to one another along parallel fold lines 13, 15, 17 and 19, respectively. The first side wall panel 12 is further defined by a raw edge 11 of paperboard material which extends parallel to the fold line 13. A first bottom fold line 21 and a first top fold line 22 extend between the raw edge 11 and fold line 13.
A first bottom panel 23 is articulated to the first side panel 12, of the prior art blank 10, along the first bottom fold line 21. The first bottom panel 23 is further defined by a side raw edge 24 which extends generally collinearly from the raw edge 11. The first bottom panel 23 is further defined by a fold line 25 which extends collinearly from the fold line 13 and by a bottom raw edge 26 which extends between the side raw edge 24 and the fold line 25. The bottom raw edge 26 typically will be disposed at an interior most location on the gable carton formed from the prior art blank 10.
A first top panel 28 is articulated to the first side panel 12 along the first top fold line 22. The first top panel 28 is further defined by a side raw edge 29 which extends collinearly from the raw edge 11 and by a fold line 30 which extends collinearly from the fold line 13. A fold line 31 extends between the side raw edge 29 and the fold line 30 to define the first top panel 28. A first top seal panel 33 is articulated to the rectangular first top panel 28 along fold line 31. A diagonal fold line extends from the intersection of fold lines 30 and 22 to a central region of fold line 31.
The second side panel 14 is further defined by a second bottom fold line 41 and a second top fold line 42. A second bottom panel 43 is articulated to the second side panel 14 along the second bottom fold line 41. The second bottom panel 43 is further defined by two converging fold lines 44, 45. A first triangular web panel 46 is articulated to the second bottom panel 43, along the fold line 44, and is articulated to the first bottom panel 23 along the fold line 25. The first triangular web panel 46 is further defined by a raw edge 47 which extends between the fold lines 25, 44. A second triangular web panel 48 is similarly articulated to the second bottom panel 43 along fold line 45. The second triangular web panel 48 is defined further by a fold line 49 which extends collinearly from the fold line 15 and by fold line 45 and raw edge 50.
A second top panel 51 is articulated to the second side panel 14 along the second top fold line 42. The second top panel 51 is defined further by converging fold lines 52 and 53. First and second triangular web panels 54,55 are articulated to the second top panel 51 along fold lines 52 and 53, respectively. The first triangular web panel 54 is further articulated to the first top panel 28, along fold line 30, and is defined further by fold line 56. The triangular web panel 55 is similarly defined further by fold line 57 which extends collinearly from the fold line 15 and by fold line 58 which extends collinearly from the fold line 56. Top seal panels 59 and 60 are articulated to the web panels 54 and 55, respectively, along the fold lines 56 and 58.
The third side panel 16 of the prior art blank 10 is further defined by a third bottom fold line 61 and a third top fold line 62. A third bottom panel 63 is articulated to the third side panel 16 along the third bottom fold line 61. The third bottom panel 63 is articulated to the second triangular bottom web panel 48 along fold line 49 and is defined further by side raw edge 65 which extends collinearly from the fold line 49 and generally orthogonal to the raw edge 50 of the bottom web panel 48; a transverse raw edge 66 which extends orthogonally from the side raw edge 65 a major distance across the third bottom panel 63; and, a diagonal raw edge 67 which extends between the bottom raw edge 66 and a fold line 64. As will be explained below in further detail, the third bottom panel 63 defines an external wall of the gable carton erected from the prior art blank 10, and the raw edges 65, 66 and 67 of the third bottom panel 63 are substantially exposed on exterior regions of the carton.
A generally rectangular third top panel 68 is articulated to the third side panel 16 along fold line 62. The third top panel 68 is articulated to the top second triangular web panel 55 along fold line 57 and is defined further by fold line 69 which extends collinearly from the fold line 17 and by fold line 70 which extends parallel to fold line 62, between the fold lines 57 and 69. A second top seal panel 72 is articulated to the third top panel 68 along fold line 70. A diagonal fold line extends from the intersection of fold lines 57 and 62 to a central region of fold line 70.
The fourth side panel 18 of the prior art blank 10 is defined further by a fourth bottom fold line 73 and a fourth top fold line 74 which extend orthogonally between the fold lines 17 and 19. A fourth bottom panel 75 is articulated to the fourth side panel 18 along fold line 73. The fourth bottom panel 75 is further defined by converging fold lines 76 and 77. A first triangular bottom web panel 78 is articulated to the third bottom panel 63, along fold line 64, and is further articulated to the fourth bottom panel 75 along fold line 76. The first triangular web panel 78 is further defined by a raw edge 79 which extends from the diagonal raw edge 67 generally orthogonal to the fold line 64. A second triangular web panel 80 is similarly articulated to the fourth bottom panel 75 along fold line 77. The second triangular web panel 80 is defined further by a raw edge 81 and by fold line 82 which extends collinearly from the fold line 19.
A fourth top panel 83 is articulated to the fourth side panel 18 along fold line 74. The fourth top panel 83 is defined further by converging fold lines 84 and 85. A first triangular web panel 86 is articulated to the third top panel 68, along fold line 69, and is articulated to the fourth top panel 83 along fold line 84. The first triangular web panel 86 is defined further by fold line 87 which extends substantially collinearly from the fold line 70. A second triangular web panel 88 is similarly articulated to the fourth top panel 83 along fold line 85. The second triangular web panel 88 is defined further by fold line 89 extending collinearly from the fold line 19 and by fold line 90. Top seal panels 91 and 92 are articulated to the web panels 86 and 88 along fold lines 87 and 90, respectively.
The side glue panel 20, of the prior art blank 10, is defined further by top and bottom fold lines 93 and 94 and by a raw side edge 95. A bottom glue panel 96 is articulated to the web panel 80, along fold line 82, and to the side glue panel 20 along fold line 93. The bottom glue panel 96 is defined further by a diagonal raw edge 97 and by a side raw edge 98 which extends collinearly from the side edge 95. A top glue panel 99 is similarly articulated to the top web panel 88, along fold line 89, and to the side glue panel 20 along fold line 94. The top glue panel 99 is defined further by a raw side edge 100 which extends collinearly from the raw edge 95 of the side glue panel 20.
The prior art blank 10 is cut and scored by the paperboard manufacturer in a conventional fashion. The paperboard manufacturer also typically will fold the glue panels 20, 96 and 99, relative to the remainder of the prior art blank 10, about the collinear fold lines 19, 82 and 89, respectively. The entire prior art blank 10 will further be folded substantially in half about the collinear fold lines 15, 49 and 57. The glue panels 20, 96 and 99 then will be securely adhered to the first side panel 12, the first bottom panel 23 and the first top panel 28, respectively, such that the fold lines 19, 82 and 89 are located substantially adjacent the raw edges 11, 24 and 29, respectively. In this folded condition, the glue panels 20, 96 and 99 will be adhered to an inner surface of the first side panel 12, the first bottom panel 23 and the first top panel 28 that will define the interior of the resulted carton erected from the prior art blank 10. It will be appreciated that according to the procedure set forth above, the folded blank will be substantially flat with the first side panel 12 being in a substantially face-to-face relationship with the fourth side panel 18 and the second side panel 14 being in a substantially face-to-face relationship with the third side panel 16. Thereafter, the folded prior art blank 10 will typically be shipped from the paperboard manufacturer to a diary or some other producer of a liquid, powder, gel, fluid, etc. to be stored in the container formed from the prior art blank 10.
With reference to FIG. 1A, a typical blank for a prior art pint or quart gable carton is identified generally by the numeral 210. The prior art blank 210 includes first through fourth rectangular side wall panels 212, 214, 216, and 218 and a side glue panel 220 which are consecutively articulated to one another along parallel fold lines 213, 215, 217 and 219, respectively. The first side wall panel 212 is further defined by a raw edge of paperboard material 211 which extends parallel to a fold line 213. A first bottom fold line 221 and a first top fold line 222 extend between the raw edge 211 and the fold line 213 to further define the first side panel 212.
A first bottom panel 223 is articulated to the first side panel 212, of the prior art blank 210, along the first bottom fold line 221. The first bottom panel 223 is further defined by a side raw edge 224 which extends generally collinearly from the raw edge 211. The first bottom panel 223 is further defined by a fold line 225 which extends collinearly from the fold line 213 and by a bottom raw edge 226 which extends between the side raw edge 224 and the fold line 225. The bottom raw edge 226 typically will be disposed at an interior most location on the gable carton formed from the prior art blank 210.
A first top panel 283 is articulated to the first side panel 212 along fold line 222. The first top panel 283 is defined further by converging fold lines 284 and 285. A first triangular web panel 286 is articulated to the first top panel 283, along fold line 284. The first triangular web panel 286 is defined further by side raw edge 289 which extends substantially collinearly with raw edge 211 and by fold line 287. A second triangular web panel 288 is similarly articulated to the first top panel 283 along fold line 285. The second triangular web panel 288 is defined further by fold line 229 extending collinearly from the fold line 213 and by fold line 290. Top seal panels 291 and 292 are articulated to the triangular web panels 286 and 288 along fold lines 287 and 290, respectively.
The second side panel 214 is further defined by a second bottom fold line 241 and a second top fold line 242. A second bottom panel 243 is articulated to the second side panel 214 along the second bottom fold line 241. The second bottom panel 243 is further defined by two converging fold lines 244, 245. A first triangular web panel 246 is articulated to the second bottom panel 243, along the fold line 244, and is articulated to the first bottom panel 223 along the fold line 225. The first triangular web panel 246 is further defined by a raw edge 247 which extends between the fold lines 225, 244. A second triangular web panel 248 is similarly articulated to the second bottom panel 243 along fold line 245. The second triangular web panel 248 is defined further by a fold line 249 which extends collinearly from the fold line 215 and by fold line 245 and raw edge 250.
A second top panel 228 is articulated to the second side panel 214 along the second top fold line 242. The second top panel 228 is further articulated to the triangular web panel 288 along fold line 229 which extends collinearly from fold line 213 and by fold line 230 which extends collinearly from the fold line 215. A fold line 231 extends between the fold lines 229 and the fold line 230 to further define the first top panel 228. A first top seal panel 233 is articulated to the rectangular first top panel 228 along fold line 231. A diagonal fold line extends from the intersection of fold lines 230 and 242 to a central region of fold line 231.
The third side panel 216 of the prior art blank 210 is further defined by a third bottom fold line 261 and a third top fold line 262. The third bottom panel 263 is articulated to the third side panel 216 along the third bottom fold line 261. The third bottom panel 263 is articulated to the bottom web panel 248 along fold line 249 and is defined further by side raw edge 265 which extends collinearly from the fold line 249 and generally orthogonal to the raw edge 250 of the bottom web panel 248; a transverse raw edge 266 which extends orthogonally from the side raw edge 265 a major distance across the third bottom panel 263; and, a diagonal raw edge 267 which extends between the bottom raw edge 266 and the fold line 264. As will be explained below in further detail, the third bottom panel 263 defines an external wall of the gable carton erected from the prior art blank 210, and the raw edges 265, 266 and 267 of the third bottom panel 263 are substantially exposed on exterior regions of the carton.
A third top panel 251 is articulated to the third side panel 216 along the third top fold line 262. The third top panel 251 is defined further by converging fold lines 252 and 253. First and second triangular web panels 254, 255 are articulated to the third top panel 251 along fold lines 252 and 253, respectively. The first triangular web panel 254 is further defined by the fold line 230 which extends collinearly with fold line 215 and by fold line 256. The second triangular web panel 255 is similarly defined further by fold line 257 which extends collinearly from the fold line 217 and by fold line 258 which extends collinearly from the fold line 256. Top seal panels 259 and 260 are articulated to the web panels 254 and 255, respectively, along the fold lines 256 and 258.
The fourth side panel 218 of the prior art blank 210 is defined further by a fourth bottom fold line 273 and a fourth top fold line 274 which extend orthogonally between the fold lines 217 and 219. A fourth bottom panel 275 is articulated to the fourth side pane 218 along fold line 273. The fourth bottom panel 275 is further defined by converging fold lines 276 and 277. A first triangular bottom web panel 278 is articulated to the third bottom panel 263, along fold line 264, and is further articulated to the fourth bottom panel 275 along fold line 276. The first triangular web panel 278 is further defined by a raw edge 279 which extends from the diagonal raw edge 267 generally orthogonal to the fold line 264. A second triangular web panel 280 is similarly articulated to the fourth bottom panel 275 along fold line 277. The second triangular web panel 280 is defined further by a raw edge 281 and by fold line 282 which extends collinearly from the fold line 219.
A generally rectangular fourth top panel 268 is articulated to the fourth side panel 218 along fold line 274. The fourth top panel 268 is articulated to the second triangular web panel 255 along fold line 257 and is defined further by fold line 269 which extends collinearly from the fold line 219 and by fold line 270 which extends parallel to fold line 274, between the fold lines 257 and 269. A second top seal panel 272 is articulated to the fourth top panel 268 along fold line 270. A diagonal fold line extends from the intersection of fold lines 257 and 274 to a central region of fold line 270.
The side glue panel 220, of the prior art blank 210, is defined further by bottom and top fold lines 293 and 294 and by a raw side edge 295. A bottom glue panel 296 is articulated to the second triangular web panel 280, along fold line 282, and to the side glue panel 220 along fold line 293. The bottom glue panel 296 is defined further by a diagonal raw edge 297 and by a side raw edge 298 which extends collinearly from the raw side edge 295. A top glue panel 299 is similarly articulated to the fourth panel 268, along fold line 269, and to the side glue panel 220 along fold line 294. The top glue panel 299 is defined further by a raw side edge 300 which extends collinearly from the raw side edge 295 of the side glue panel 220.
The prior art blank 210 is cut and scored by the paperboard manufacturer in a conventional fashion. The paperboard manufacturer also typically will fold the glue panels 220, 296 and 299, relative to the remainder of the prior art blank 210, about the collinear fold lines 219, 282 and 269, respectively. The entire prior art blank 210 will further be folded substantially in half about the collinear fold lines 215, 230, and 249. The glue panels 220, 296 and 299 then will be securely adhered to the first side panel 212, the first bottom panel 223 and the first top panel 283, respectively, such that the fold lines 219, 282 and 269 are located substantially adjacent the raw edges 211, 224 and 289, respectively. In this folded condition, the glue panels 220, 296 and 299 will be adhered to inner surfaces of the first side panel 212, the first bottom panel 223 and the first top panel 283 that will define the interior of the resulted carton erected from the prior art blank 210. It will be appreciated that according to the procedure set forth above, the folded blank will be substantially flat with the first side panel 212 being in a substantially face-to-face relationship with the fourth side panel 218 and the second side panel 214 being in a substantially face-to-face relationship with the third side panel 216. Thereafter, the folded prior art blank 210 will typically be shipped from the paperboard manufacturer to a diary or some other producer of a liquid, powder, gel, fluid, etc. to be stored in the container formed from the prior art blank 210.
The diary or other producer will have the necessary equipment for forming and sealing the quart or half gallon prior art blank 10 or 210 into a gable carton. The equipment will be operative to form the collapsed prior art blank 10 or 210 into a generally tubular open ended structure. Thereafter, the bottom end of the open ended tubular structure is closed by folding the second and fourth bottom panels 43 and 75 or 345 and 375 inwardly about the second and fourth bottom fold lines 41 and 73 or 241 and 273, respectively. Next, the first and third bottom panels 23 and 63 or 223 and 263 will then be folded inwardly about the first and third bottom fold lines 21 and 61 or 221 and 261, respectively. This latter folding is carried out such that the first bottom panel 23 or 223 leads the third bottom panel 63 or 263. Thus, the bottom raw edge 26 or 226 of the first bottom panel 23 or 223 will be located interiorly relative to the third bottom panel 63 or 263. However, the side raw edge 24 or 224 of the first side panel 23 or 223 will be substantially exposed to the external environment along a bottom edge of the gable carton formed from the prior art blank 10, as shown in FIG. 2, or 210 as shown in FIG. 2A. The raw edges 65, 66 and 67 or 265, 266 and 267, of the third bottom panel 63 or 263, will be similarly exposed in a position extending substantially centrally across the bottom of the resulting gable carton formed from the prior art blank 10, 210. The folded bottom panels 23, 43, 63 and 75 or 223, 243, 263 and 275 are then adhered to one another in overlapping relationship by a convention hot melt application. The above described gable carton forming process is carried out by placing the folded bottom of the carton on a pressure pad, and by urging a mandrel downwardly in through the open top end of the partially formed gable carton structure. The sealing of the bottom of the carton is achieved by appropriate application of heat and pressure, by the pressure pad and the mandrel.
More effective sealing of the carton bottom may be achieved by providing short linear embossments at desired locations on the pressure pad. These embossments are disposed to orthogonally intersect certain fold lines on the bottom of the panel. Additionally, the embossments may be disposed at locations on the third bottom panel that register with edge regions of panels located interiorly of the third bottom panel. These short discontinuous embossments provide a more secure sealing at selected locations on the bottom of the panel.
As a result of the above describe assembly, the prior art paperboard blank 10 or 210 is formed into an open-topped sealed bottom carton. The open-topped carton can be conveyed to a filling station, of the dairy or other production facility, where the product contents are deposited within the open-topped sealed bottom carton. The open-topped sealed bottom carton is then conveyed to a top sealing station where the second and fourth top panels 51 and 83 of the half gallon container or the first end third top panels 83, 251 of the quart blank are bent toward one another and where the first and third top panels 28 and 68 of the half gallon blank and the second and fourth top panels 228, 268 of the quart blank are then bent toward one another to close the top of the open-topped sealed bottom carton. The various top panels are then sealed by application of appropriate heat and pressure to the seal panels 33, 59, 60, 72, 91 and 92 or 233, 259, 260, 272, 291 and 292 and form a completely sealed gable top container.
It is to be appreciated that the paperboard material, from which the prior art blank is formed, is a fibrous material which has a natural tendency to absorb a liquid. The opposed faces of the prior art blank typically will be coated with a plastic or foil to render these surfaces substantially impermeable to liquids and/or gases. However, the edge regions of the prior art blank are capable of absorbing liquid and function as a "wick" which enable the absorbed liquid(s) to travel from an edge location in the paperboard material toward an interior location spaced from the edge. The absorption of a liquid(s) and the wicking of the absorbed liquid(s), from edge regions of the glue panels disposed interiorly on the carton, can be prevented by removing all or a major portion of the paperboard material along the raw edge, but leaving the coating or foil. The remaining coating or foil can then be folded over the raw edge to seal the raw edge and prevent absorption and wicking of liquid(s).
It is to be appreciated that gable cartons, filled with milk or other beverages, often will be transported along conveyors and may be stored in trucks or coolers where liquid may accumulate on a transportation or storage surface, if these surfaces are not constantly maintained clean. Thus, the external raw edges of the formed gable carton, particularly the raw edges near the bottom of the gable carton, are likely to absorb and wick a lubricant(s) or some other fluid(s) with which the gable carton may eventually come into contact.
It is to be appreciated that the filled and sealed gable cartons may be stored for many days, thus allowing ample time for such extraneous liquids to be wicked into the paperboard material and cause discoloration of the carton and/or contamination of the liquid, powder, gel, or other contents stored therein. Furthermore, the wicking of liquids into the paperboard material, defining the bottom of the carton, can affect the overall structural integrity of the formed gable carton or cause leakage of the material stored in the carton.
In particular, it is the inability of previous bottom sealing methods and apparatus to adequately and properly seal the multitude of different papers comprising the range of multilayer folded bottoms of such cartons. The sealing process is particularly important as it relates directly to the shelf life of the fluid product and retardation of spoilation of the product contained therein as well as to the integrity of the container. Obviously the longer the shelf life of the product, the more economical the production.
As is well known in the art, there are numerous examples of carton sealing apparatus. For example, U.S. Pat. No. 3,912,576 to Braun relates to a sealing apparatus for sealing a rectangular end closure of the thermoplastic coated paperboard by ultrasonic vibrations. Braun's apparatus includes a mandrel or backup member and an ultrasonic vibrating pressure pad tool. The ultrasonic vibrating tool, which provides a bow-tie type profile sealing configuration on its face, engages the end closure opposite the mandrel and, by squeezing the end closure therebetween, seals the folded multilayer rectangular bottom end closure of the container.
U.S. Pat. No. 3,971,300 to Bachner also relates to a pressure pad in combination with a mandrel. Bachner's pressure pad has a multiplicity of surfaces which lie in at least two distinct planes and are shaped to receive and engage the desired carton sections, specifically the tabs and panels of the folded bottom closure of the carton thus placing appropriate pressure along these seams to properly seal the same.
The above referenced methods and apparatus have proved adequate to seal and close the bottom of thermoplastic multilayered folded container for a relatively short period of time. However, there is a need to improve the seal formed on the bottom of the gable container to reduce or eliminate the tendency of the raw edges to absorb and/or wick moisture which is applicable for a wide range of shapes and sizes of the gable cartons.